Line a 9x9 pan with parchment, leaving an overhang. Arrange 8 ice cream sandwiches in a single layer to cover the bottom.

Spread half the softened ice cream over sandwiches. Sprinkle half the sprinkles. Freeze 15 minutes until firm.

Add second layer of 8 sandwiches. Spread remaining ice cream on top. Smooth with a spatula, adding milk if too stiff.

Cover surface with whipped cream and the rest of the sprinkles. Wrap pan and freeze at least 4 hours or overnight.

Unwrap using parchment overhang. Slice with a warm knife, wiping between cuts.